Aircraft engines are typically mounted laterally on a fuselage of an aircraft via a pylon structure. Each pylon structure includes generally C-shaped yokes, and generally radially extending spars. Conventional engine mounting systems connect the yoke of the pylon structure and the aircraft engine by means of rigid clevis mounts 10 (FIG. 1). Conventional rigid clevis mounts include two symmetrical flanges 12.
Rotational imbalance of the aircraft engine causes vibration from the engine to be transmitted into the yoke of the pylon structure, through the intermediate spar thereof, and into the aircraft fuselage resulting in noise and vibration in the aircraft cabin. Such vibrations are referred to as “dynamic forces.” In the case of dynamic forces (vibration), “compliance” is the ratio of the excited vibrational amplitude (angular or linear displacement) to the magnitude of the force. As used herein, “stiffness” refers to how far an aircraft fuselage moves from the vibration force of the aircraft engine and is measured in pound force/inches (lbf/in). The higher the compliance (i.e., the lower the stiffness), the better the high frequency vibration isolation. Significant dynamic forces from all six degrees of freedom of the aircraft engine often exist; therefore, complete six degree-of-freedom vibration load isolation is often desired.
Unfortunately, conventional rigid clevis mounts provide little or no vibration isolation due to their high stiffness (i.e., low compliance). While conventional rigid clevis mounts provide tunable stiffness to make more compliant in two axes (locally) by adjusting the length, width and/or height of the flanges thereof, and in concert with multiple rigid clevis mounts and/or vibration isolation struts, help support the engine in all six degrees of freedom, they are only tunable in a relatively small range before becoming susceptible to stress failures (if the flanges are too thin) or becoming too heavy for optimum aircraft efficiency (if the flanges are too thick).
Accordingly, it is desirable to provide resilient aircraft engine mounts and aircraft engine mounting systems including the same. In addition, it is desirable to provide resilient aircraft engine mounts that provide compliance without substantial cross-axis reaction forces, that are compact and lightweight, easily stiffness tunable to make more compliant over a greater range than conventional clevis mounts, in three degrees of freedom (per resilient aircraft engine mount) (translational degree of freedom) to support all six degrees of freedom, and that provide an easy replacement or conversion from rigid clevis mounts in engine mounting systems.